The guiding principle in collective motion is the emergence of coordinated behavior or patterns from the interactions of individual entities within a group. The collective motion refers to the collective behavior exhibited by abundance of entities, such as the flocking of birds, schools of fishes, or herds of animals, where individuals move together in a coordinated manner. One of the key principles underlying collective motion is known as "self-organization." Self-organization mainly refers to the spontaneous emergence of order and organization in a system without external control or coordination. In the context of collective motion, self-organization occurs when the interactions among individuals give rise to collective behavior patterns, such as flocking or schooling (see the Video).
Several factors contribute to the emergence of collective motion. One important factor is local interaction or alignment. Individuals in a group align their movements based on the movements of their neighbors, leading to a collective alignment and coordination of movement. This alignment can occur through simple rules, such as aligning with the average direction of nearby individuals or aligning with the perceived motion of neighbors. Another crucial factor is the balance between cohesion and separation. Cohesion refers to the tendency of individuals to stay close together, while separation refers to the desire to maintain a safe distance from others. The interplay between cohesion and separation helps maintain the overall structure and integrity of the group while allowing for individual movement and exploration.
Furthermore, individual perception and responsiveness play a significant role in collective motion. Each entity in the group needs to perceive and respond to the movements and positions of its neighbors. By sensing and reacting to the local environment, individuals can maintain alignment and avoid collisions, contributing to the overall coordination of the group. Additionally, external environmental factors, such as obstacles or predators, can influence collective motion. The group may respond collectively to external threats, adjusting their movements to avoid danger or maximize their chances of survival.
The specific mechanisms can vary across different species and contexts within general principles of collective motion. We use mathematical models, computer simulations, and experimental observations to study and understand the underlying mechanism and dynamics to find new principles of collective motion in various systems.